Osinski, G.R., Grieve, R.A.F., Hill, P.J.A., Simpson, S.L., Cockell, C., Christeson, G.L., Ebert, M., Gulick, S., Melosh, H.J., Riller, U., Tikoo, S.M., Wittmann, A., 2019. Explosive interaction of impact melt and seawater following the Chicxulub impact event. Geology 48, 108-112.

https://doi.org/10.1130/G46783.1 The impact of asteroids and comets with planetary surfaces is one of the most catastrophic, yet ubiquitous, geological processes in the solar system. The Chicxulub impact event, which has been linked to the Cretaceous- Paleogene (K-Pg) mass extinction marking the beginning of the Cenozoic Era, is arguably the most significant singular geological event in the past 100 million years of Earth's history. The Chicxulub impact occurred in a marine setting. How quickly the seawater re-entered the newly formed basin after the impact, and its effects of it on the cratering process, remain debated. Here, we show that the explosive interaction of seawater with impact melt led to molten fuel - coolant interaction (MFCI), analogous to what occurs during phreatomagmatic volcanic eruptions. This process fractured and dispersed the melt, which was subsequently deposited subaqueously to form a series of well-sorted deposits. These deposits bear little resemblance to the products of impacts in a continental setting and are not accounted for in current classification schemes for impactites. The similarities between these Chicxulub deposits and the Onaping Formation at the Sudbury impact structure, Canada, are striking, and suggest that MFCI and the production of volcaniclastic-like deposits is to be expected for large impacts in shallow marine settings.

Ouyang, G., She, Z., Papineau, D., Wang, X., Luo, G., Li, C., 2020. Dynamic carbon and sulfur cycling in the aftermath of the Lomagundi-Jatuli Event: Evidence from the Paleoproterozoic Hutuo Supergroup, North China Craton. Precambrian Research 337, 105549.

http://www.sciencedirect.com/science/article/pii/S0301926819304796 13 The unprecedented positive δ C excursion in carbonates deposited between 2.2 and 2.0 Ga, known as the Lomagundi-Jatuli Event (LJE), has been documented globally and linked to the rise of atmospheric oxygen. Increasing oxidation inevitably changed the atmosphere-hydrosphere system, but few chemostratigraphic or quantitative constraints for the aftermath of this event exists. Here, we describe a ~200 m-thick carbonate succession in the Huaiyincun Formation, Hutuo Supergroup, ~2.0 - 1.9 Ga, from the North China Craton. There is a lithological transition from pink-purple dolostones to grey dolostones at ca. 91.6 mabove the base of the Huaiyincun Formation. The former are more enriched in hematite and detrital minerals, whereas the latter contain more organic matter but almost no detrital phases. Meanwhile, the frequent occurrence of tempesite structures, along with the abrupt decline of stromatolites in the upper Huaiyincun Formation, suggest a storm- dominated environment. These distinct features within the Huaiyincun Formation reveal increased water depth during a transgression event. Two types of Raman spectra of organic matter were found in the lower and upper Huaiyincun Formation, respectively, which is proposed to be the result of variable oxidation. 13 34 At 65.6 m, 26 mbelow the lithological transition (~91.6 m), remarkable decreases in both δ C and δ S carb CAS are observed. This discordance between C-S isotopic excursions and sedimentological and mineralogical 13 34 variations argues against a seawater depth gradient effect of the δ C and δ S curves. Instead, the decline carb CAS 13 13 of δ C rather correlates with the negative δ C excursions in ca. 2.0 Ga carbonates from Gabon and carb carb Russia, known as the Shunga-Francevillian Event (SFE). The result of the quantitatively constrained paleo- 2- seawater [SO ] suggests a crash of the seawater sulfate reservoir compared with that during the preceding 4 sw 34 LJE. However, the decreased δ S and increased CAS concentration towards the top of the study unit CAS 34 13 represent the recovery of seawater sulfate reservoir. The coordinated decline in δ S and δ C values is CAS carb likely related to enhanced oxidation of continental pyrite and organic matter in the aftermath of the LJE. The Huaiyincun Formation therefore represents a critical interval that recorded dynamic carbon and sulfur cycles after the LJE.

Ovchinnikov, D.V., Pokrovskiy, O.I., Kosyakov, D.S., Bogolitsyn, K.G., Ul'yanovskii, N.V., Falev, D.I., 2020. Evaluation of temperature and pressure effects on retention in supercritical fluid chromatography on polar stationary phases. Journal of Chromatography A 1610, 460600.